过量表达甘菊CBF1基因提高拟南芥抗旱耐盐能力

CBF是一类植物特异性、具有多种功能的转录因子。本研究将从甘菊(Chrysanthemum lavandulifolium)中分离的ClCBF1基因构建到植物表达载体pBI121上,并采用农杆菌介导的花序浸染法对拟南芥(Arabidopsis thaliana)进行遗传转化,共获得4个转基因株系经过抗性筛选和RT-PCR验证,对其中表达量较高的3个转基因株系进行研究,结果表明:在150mmol·L~(-1)甘露醇培养基中转基因拟南芥的种子萌发率和根长平均为野生型的2.0倍和1.2倍,在150mmol·L~(-1) NaCl培养基中转基因拟南芥种子萌发率和根长平均为野生型的1.1倍和1.4倍;在干旱和盐胁迫条件下,转基因拟南芥幼苗的成活率高于野生型,并且超氧化物歧化酶(SOD)和过氧化物酶(POD)活性显著高于野生型(P0.05),丙二醛(MDA)含量及相对电导率显著低于野生型植株(P0.05)。说明ClCBF1基因在拟南芥受到干旱和盐胁迫过程中发挥一定作用。     

白羊草BiMYB52基因的克隆及转基因拟南芥抗旱性表达分析

白羊草(Bothriochloa ischaemum)是一种耐旱的优良乡土草种。为了探索白羊草转录因子MYB的结构和功能,本研究以白羊草转录组测序中筛选出的一段对干旱胁迫响应表达量变化显著的MYB序列为基础,采用基于拓扑异构酶快速克隆法从白羊草中克隆了一个R2R3-MYB基因BiMYB52,该基因编码237个氨基酸。为了深入研究BiMYB52基因的抗旱性,利用染色体步移技术扩增出了BiMYB52启动子序列,构建了pCAMBIA1301-BiMYB52过表达载体,采用农杆菌介导的花序侵染法对拟南芥(Arabidopsis thaliana)进行遗传转化,然后对野生拟南芥和转基因拟南芥进行干旱胁迫处理。结果表明,干旱胁迫复水后,转基因拟南芥的存活率显著高于野生拟南芥,丙二醛(Malondialdehyde, MDA)含量是干旱胁迫后转基因拟南芥的显著低于对照,脯氨酸(Proline, Pro)含量则显著高于对照。由此推测BiMYB52基因可能增加了拟南芥对干旱胁迫的抵抗能力。这为白羊草抗旱育种提供候选基因和理论基础。     

PEG与NaCl等渗胁迫对华北驼绒藜种子萌发及幼苗生长影响的差异

设置不同等渗梯度(0MPa、-0.4MPa、-0.6MPa、-0.8MPa、-1.0MPa)模拟研究生理干旱(采用NaCl模拟)与土壤干旱(采用PEG模拟)对华北驼绒藜种子萌发和幼苗生长的影响。结果表明:与对照(CK,0MPa)相比,轻度NaCl胁迫(-0.4MPa)对种子发芽率、发芽指数和幼苗活力指数无显著影响,中度胁迫(-0.6MPa)使三者均大幅增加,重度胁迫(-0.8～-1.0MPa)使种子平均发芽率、发芽指数显著降低但对幼苗活力指数无明显影响;轻度和中度PEG胁迫(-0.4～-0.6MPa)对发芽率、发芽指数无显著影响,但显著提高了幼苗活力指数,重度PEG胁迫(-1.0MPa)使发芽率和发芽指数均显著降低。对幼苗而言,NaCl胁迫对其无明显影响,但轻度、中度、重度PEG胁迫使根长度均显著增加。总而言之,两种胁迫对种子萌发的影响极为不同,轻度、中度生理干旱促进种子萌发,重度生理干旱抑制种子萌发,而土壤干旱胁迫对萌发无明显影响;两种胁迫对幼苗生长的影响主要与二者能否促进根系生长有关,生理干旱不影响根系生长,土壤干旱促进根生长。     

无芒隐子草花序不同部位种子萌发期光照需求及抗旱性综合评价

以无芒隐子草(Cleistogenes songorica)花序不同部位的种子为材料,采用聚乙二醇(PEG-6000)模拟不同水势(0.0,-0.2,-0.4,-0.6,-0.8 MPa)研究种子萌发期光照需求并进行抗旱性综合评价。结果表明:花序各部位种子的发芽率、发芽势、发芽指数以及活力指数等指标随着渗透势的降低而减小。适度的干旱胁迫促进胚根生长,然而干旱胁迫对胚芽生长则始终起到抑制作用。无芒隐子草花序各部位种子在萌发过程中均需要光照条件,在黑暗环境下其种子发芽率、发芽势等指标均显著下降,胚根长度与胚芽长度亦显著低于光照条件。用模糊数学隶属法综合评价各部位种子的抗旱性,结果表明其抗旱性自高至低依次为:中部下部上部顶部,鞘藏小穗中种子的抗旱性远高于顶穗中的种子,在无芒隐子草的建植中应该优先考虑。     

紫花苜蓿和黄花苜蓿种子萌发期对PEG模拟干旱胁迫的响应

为了探知紫花苜蓿和黄花苜蓿种子萌发期对逆境胁迫的适应能力,采用8个不同浓度的聚乙二醇(PEG-6000)溶液模拟干旱条件,研究了紫花苜蓿和黄花苜蓿种子萌发和幼苗生长对干旱的响应,评价了二者的抗旱性。结果表明,在非干旱和干旱条件下,紫花苜蓿的发芽率、发芽势、发芽指数、活力指数、根长、苗长均高于黄花苜蓿。轻度干旱(PEG 4%)可促进两种苜蓿的种子萌发;中度干旱(PEG 8%~12%)对两种苜蓿的种子萌发和幼苗生长产生显著抑制作用;重度干旱(PEG 16%~20%)抑制作用更强。黄花苜蓿受抑制程度大于紫花苜蓿。极端干旱条件(PEG 24%~32%)下,两种苜蓿的种子完全受到抑制,不能萌发,但种子活力依然存在。复水至水分条件适宜时,仍能萌发。参考隶属函数法采用多个相对指标的综合评价结果表明紫花苜蓿种子萌发期的抗旱性高于黄花苜蓿。     

6种高寒牧区禾本科牧草抗旱性研究与评价

本研究选择在高寒地区种植多年的6种禾本科牧草,对其进行种子萌发期和苗期抗旱性试验。用PEG模拟水分胁迫及连续干旱法来研究干旱胁迫对种子发芽率及种子幼苗期生理指标的影响,以此来综合评价六种禾本科牧草的抗旱性强弱。种子萌发期研究结果表明,5%的PEG浓度有效促进种子萌发,高PEG浓度显著抑制种子发芽率。经连续干旱胁迫法处理的苗期牧草,测定其相对含水量、丙二醛含量、可溶性糖含量和叶绿素含量四项生理指标。对两个时期隶属值综合分析可知,六种牧草的抗旱性强弱为：草原看麦娘（Alopecurus pratensis） > 无芒雀麦（Bromus inermis） > 同德短芒披碱草（Elymus breviaristatus） > 同德贫花鹅观草（Roegneria pauciflora） > 大颖草（Roegneria grandiglumis） > 扁穗冰草（Agropyron cristatum）。     

日本结缕草ZjZFN1基因对拟南芥的转化及其耐旱性分析

锌指蛋白在植物干旱胁迫中起重要作用,尽管已经在各种植物中克隆并鉴定了编码这些蛋白质的基因,但是它们在日本结缕草中的功能和潜在的转录机制还不清楚。通过花序侵染法将ZjZFN1基因及其启动子转化拟南芥,并通过草铵膦/潮霉素抗性筛选和PCR鉴定,获得转基因株系。ZjZFN1的启动子能够驱动GUS基因的表达,在甘露醇处理下的GUS基因表达水平显著高于对照;在拟南芥中过表达ZjZFN1降低了种子发芽率,减弱了植物对干旱胁迫的适应性和植物在干旱胁迫下的生长状况;干旱处理后,转基因植株中的丙二醛含量高于野生型植株,而脯氨酸含量显著低于野生型植株;实时荧光定量分析表明对过表达ZjZFN1的拟南芥进行干旱处理后,POD、SOD、P5CS、LEA的表达水平降低,而APX的表达水平升高。ZjZFN1基因的过表达可减弱植物的耐旱性,为进一步开发利用该基因奠定基础。     

羊草LcCBF6基因的表达特性和功能研究

羊草是我国重要的牧草和生态草资源,具有耐盐碱、耐旱、耐低温等特性,是天然的抗逆基因资源库.CBF/DREB属于AP2转录因子家族,在植物抗逆中发挥着重要作用.本研究克隆得到羊草LcCBF6(Leymus chinensis C-repeat binding factor 6)基因,该基因含有AP2结构域,编码245个氨基酸.氨基酸序列比对发现,LcCBF6与蒙古冰草和黑麦的CBF6蛋白的同源性分别为92％和91％.组织特异性表达模式分析表明,LcCBF6基因在羊草根、叶、种子中均有表达,且受盐胁迫诱导表达.过表达LcCBF6能显著提高转基因拟南芥的抗盐性.在盐胁迫条件下,转基因株系的绿色子叶数、根长、植株生物量以及存活率等均明显高于野生型.上述结果表明羊草LcCBF6基因在提高植物盐胁迫抗性方面发挥了重要的作用,将为牧草及重要农作物抗逆分子育种提供优异的基因资源.     

PEG与低温对法国百里香种子萌发的影响

以法国百里香(Thymus vulgaris)为材料,研究了PEG模拟干旱胁迫和低温对种子萌发和幼苗生长的影响,旨在探索进口百里香种子播种育苗的适宜条件。结果表明,温度、干旱及其互作对法国百里香种子萌发和幼苗生长均有显著影响。0~10%PEG-6000水分条件下,8~24℃下法国百里香种子均能良好萌发,其中在10~12℃时发芽率最高,达79.3%,显著高于其余各处理(P0.05)。当PEG-6000达15%时显著抑制其萌发,至30%PEG-6000时仅在22~24℃下少量萌发。萌发后,当温度为22~24℃,根长、茎长均显著高于其他处理。种子和幼苗生长均表现出对PEG模拟干旱胁迫和低温不同的响应。     

柠条、红豆草种子及幼苗抗旱性的研究

PEG模拟干旱条件下，柠条种子相对发芽率显著高于红豆草，证明红豆草种子萌发适应干旱的能力不如柠条。盆栽幼苗断水干旱时，二种牧草组织相对含水量，植株相对生长率的降低与其抗旱性呈正相关；膜透性的增加与其抗旱性呈负相关。综合诸项指标得出柠条幼苗的抗旱能力要大于红豆草。     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Changes in proportion of canine urinary calculi composed of calcium oxalate or struvite in specimens analyzed from 1981 through 2001

The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.